Symptoms

File-level backup fails with:

Fatal protocol error

Example of the error log: click to expand

Error 0x29b0002: Unknown error occurred while backing up.
| trace level: error
| line: 0xba19e88dc5fea14f
| file: d:\491\processor\backup\backup_file.cpp:1014
| function: DaProcessor::Backup::_DoFileOperation
| $module: disk_bundle_vsa64_24476
|
| error 0x29b0002: Fatal protocol error
| line: 0x5f25c37074a54438
| file: d:\491\processor\backup\archive3_file_backup.cpp:743
| function: `anonymous-namespace'::Archive3FileBackupBuilder::Write::<lambda_19b99a59afe4f797d1785e5ee0a730c2>::operator ()
| function: file_backup_run
| path: /1/r6728-69F3A0AF-8145-4E19-9555-41095545E66F-B8CCE639-F100-435D-AFBF-D73E7382A98DA.tibx
| $module: disk_bundle_vsa64_24476

Cause

Issue in the product - an incorrect error message is displayed. The real error is "File not found"

The error message will be improved in the next release of Acronis Cyber Cloud.

Troubleshooting

Acronis Cyber Protect Cloud: product behavior has been improved in Acronis Cyber Protect 20.11 (Agent build 25837). Please update to the latest build.

If the issue reproduces with version 20.11 or newer, please collect System report from the affected system and gather Process Monitor Log while reproducing the issue; contact Acronis Customer Central with a reference to this article.

Acronis Cyber Protect 15:

1. Check whether the source files (what to back up) are available on the agent machine.

2. If the files are available, collect system information and contact Acronis Customer Central with reference to this article.